Progress in the therapy of intracranial hypertension has been hampered by our inability to define with precision all aspects of the dynamics of cerebrospinal fluid pressure (Pcsf)--the mechanisms for its development and change. Complex interactions among craniospinal subsystems place the problem of cerebrospinal fluid pressure dynamics beyond simple analytic solution. Similar complex physical problems have been solved by application of the various techniques of systems engineering. Our objective is to apply those techniques to the problem of Pcsf dynamics. In pilot work, we have developed a first generation computer simulation of Pcsf dynamics. In the proposed work we will develop a more advanced computer simulator of the dynamics of this system. This simulator will be developed in parallel with a carefully constructed series of experimental perturbations of the Pcsf system in baboons. We view computer simulation, not as an end in itself, but as a technique that will allow us to explore the complex interactions which ultimately result in alterations in the level of Pcsf. The immediate benefit of these experiments will be improved understanding of the causes of intracranial hypertension; the long range benefit will be the application of model following techniques to improve the management of patients with intracranial hypertension.